Replacing the house batteries

Forum for both AC and DC electrical components. From engine alternator to dashboard, inverter to batteries, and everything electrical in-between.
Robert K
Posts: 105
Joined: Mon Oct 28, 2019 2:27 am

Replacing the house batteries

Post by Robert K »

I need to replace the 4 house batteries.
Have been using deep cell marine for the last set about 7 yrs
Presently only boondocking is overnights Walmart.

In the spring of 2022 we hope to go out west for 3-5 months, and will be putting on probably 3-400 watts of solar for more boondocking

Thinking 6 volt
Any ideas would be helpfull also any good places to buy from

Thanks
Bob
96 Serengeti 37'
3126 Cat
6 speed Allison
2011 jeep wrangler towd
astrnmrtom
Posts: 167
Joined: Thu Oct 31, 2019 8:49 pm

Re: Replacing the house batteries

Post by astrnmrtom »

Batteries are like tires and oil, everyone has their own preference and a lot has to do with your budget. Quite a few people suggest Sam's Club or Costco Golf cart batteries as being best bang for the buck, especially if you aren't intending on heavy use. Trojan is the other popular brand and is in fact, the battery everyone compares to.

My Serengeti had 4-12V Interstate deep cycles, which had been abused and needed replacing before we headed off to full time. I expected to be doing regular boondocking and have a residential refrigerator, so I decided to switch to 4-6V batteries. I decided to spend the extra money on AGMs so I wouldn't have to bother with monitoring the water. I chose VMAX XTR6, 235amp hour GC-2s. Bought them off Amazon and they shipped for free. I've only had them a short time, and one week long boondocking trip and they work well. I have 600 watts of solar, and combine that with some generator time - usually an hour in the am while cooking/fixing coffee for bulk charge, then let the solar finish them off. I topped them off with an hour of generator time around 9pm (it was early spring and dark by then) - and by morning I was at 80% SOC - and that was with some furnace time too. Probably would have been fine without the evening top off.

It really helps to do an energy audit to see what your average usage is. I used to do fine with 300 watts of solar, and the original 4-12V Interstates as long as I was frugal with my power, and this was before the residential fridge. Just a little TV and computer use, and that's about it.

Before deciding on the VMAX, I looked at DECA and Costco and priced Crowns at my local RV shop. Nearest Trojan dealer was almost 100 miles away so I didn't check them out.

One other thing regarding my switch to 6V was I have to modify my battery tray. The 6Vers were just a tiny bit too wide to fit, so I had to take a grinder and remove the angle iron dividers, and add a treated plywood bottom to the tray. Strapped the new batteries in with ratchet straps. Of course I had to change the way the batteries were wired from 4-12v in parallel, to two 6V in series to make 12V, then wired in parallel with second pair also in series. I was lucky because I was able to use the existing cables.

Batteries, solar, and boondocking is a real rabbit hole of opinions and styles. From cheap batteries and a couple panels, to 2KW solar and Lithium Ion banks controlled and monitored by computer.

One thing I've read that seems pretty universal and that is whatever you chose, take care of the batteries and you'll be good to go. Don't run them below 50% and be sure they are completely re-charged and you'll be good for many years. You can get a battery monitor, or regularly check SOC with a hydrometer.

Hope this helps,
Tom and Pris Masterson, w/ Buddy the 18 year old Siamese cat.
1998 Serengeti 3706
300hp Cat 3126, Allison 3060
900 Watts of Solar
17cf, Fisher & Paykel residential Refrigerator
Dragging four telescopes around the US seeking dark skies.
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: Replacing the house batteries

Post by TDJohn »

Bob,

GC batteries will have more capacity and live longer, which will make your boondocking experience more pleasant.
On my coach I am currently using four 6V Crown CR-260 golf cart batteries. They are rated for 260 amp/hrs, so with four of them, that is 520 amp/hrs of total capacity, 260 amp/hrs of usable capacity. The batteries are almost five years old and have been performing as great as when I just got them. In my humble opinion, Crown is slightly better than Trojan, but at a better price. The nice thing about this battery is it is 7.06 in wide, when most other brand GC batteries are 7.2 to 7.3 in width. This slightly narrower battery made the difference, where it just fit into the original battery tray, without the need of modifying anything. The fit was very tight, we had to squeeze them in there but it worked out well. Now I don't know if your battery tray is exactly the same as mine, but it is something worth looking into. A few years back, a fellow Safari owner upgraded to GC batteries, he just put 6 inch boards to raise the floor of the tray above the metal angle iron dividers and then strapped the batteries down, so this might be an option if you choose to go with a different brand.
For what it's worth, here is some comments from a boat forum, by a fellow who was in the Golf Cart Battery business for a long time.

[ Re: Are Trojans that much better?
Hi Everyone, I haven’t posted much on the forum as I usually only read and learn. I love this discussion of batteries and all the information that I am reading. Having been in the Golf Cart Battery business for many years I just wanted to chime in here.

Firstly...the batteries that you buy from Sam’s, Costco, BJ’s etc. that are labeled Duracell, Energizer, Ray-o-Vac and who knows how many other “Buzz word Brands” are for the most part distributed and privately labeled by East Penn or Johnson Controls. However, please don’t conclude that because they are sold by East Penn or JCI that they are made by them. Most if not all of the cheaper batteries are made in Equator or Mexico. No they’re not made in China….apparently our closer 3rd world industrials have lack of distance on their side or whatever.

Trojans are probably one of the best batteries on the market...just ask them. That said, an equally good battery would be “Crown”, Google it. You can find Crown at more competitive pricing than Trojan but not as cheap as the imports.

On “Seawings” I use 6 Crown CR235 6 volt batteries, I get the better quality, same warranty as Trojan (18 months) but not the huge price tag. I choose these as I believe they are the best value for the dollar.

The bottom line on all batteries that I’ve dealt with (and that’s about all of them) is if you treat them right, they will treat you right. Think of them as a horse...you wouldn’t stick a horse in a barn for a year or two with out feeding or watering it. Like wise you wouldn’t stick $400-$700 worth of batteries in a boat with inadequate charging and watering. I’ve seen Trojans, Crowns and Duracell/Deka all last 8 years and I’ve seen them last 8 months.
]

Since you are going solar, I highly recommend that you read the blog written by Handy Bob Solar. www.handybobsolar.com
He was using solar in a 5th wheel, full-timing for about 15 years (he now lives off grid in a house he built himself), starting around '99 when solar was expensive and not as popular, and there was also a lot of ignorance out there at that time regarding voltage loss due to inadequate wiring, also inadequate charge voltage for solar application, especially when the winter solar days are very short. He figured all this stuff out and has helped a lot of people along the way, including correcting/improving botched installations. His article, labeled "The Battery Charging Puzzle" is key to read, even though I suggest to read his whole blog and take notes. This will help you to avoid the common pitfalls.

Considering the cost of batteries, I strongly suggest that you get a shunt based battery monitor. There are many brands out there, I use the Trimetric TM2030RV, made by Bogart Engineering. I highly recommend it, as it is very accurate and simple to use. Bogart also makes a 30amp charge controller (SC2030) that works in conjunction with the Trimetric, to fine tune the charge algorithms. The Trimetric can work with up to two of those charge controllers. This is the system I have set up on my coach (960W), and it has more than exceeded my expectations. When comparing to other solar installations and max charge amperage output, I find that my system puts out more amps per rated watt of solar than many out there, it is a lot of bang for the buck. If you want more details on my setup PM me.
BTW, the reason I have a large amount of solar, is because I have to be able to charge my mobility scooter overnight and then recover the next day. It works very well in the summer, even when there are cloudy days. On shorter days, I could use more panels, as I'm not able to tilt them, but the possible expansion is for another day at this point.

One last point, if you happen to run you batteries below 50% every once in a while, it is not the end of the world, as it really won't hurt them, as long as you recharge them back up promptly and you equalize them after a deep discharge. Of course shallow cycles do provide a much longer battery life overall.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: Replacing the house batteries

Post by TDJohn »

Tom,

Since you have a residential refrigerator, one thing you might want to consider doing, on those days when you need to conserve on power, is putting a good quality timer on your refrigerator. The new units are very well insulated and at night, when no one opens up the refrigerator, you could easily get by with one ON cycle for about 20 minutes in the middle of the night. The rest of the night it can stay off and save power. If you have a thermometer in the refrigerator that has an external readout, it will help you see how much cooling you actually need overnight. This can be especially helpful during short solar day and/or prolonged rainy/cloudy days. It will also help minimize generator run time. :D
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
Robert K
Posts: 105
Joined: Mon Oct 28, 2019 2:27 am

Re: Replacing the house batteries

Post by Robert K »

Thanks John and Tom,
Looking at duracell 215 ah at $110 each but they are 7.125 "wide and that is real tight. The Crown's at 7.06 are 1/16" narrower.
Will look and see if I can find crown retailer
Thanks
Bob
96 Serengeti 37'
3126 Cat
6 speed Allison
2011 jeep wrangler towd
Robert K
Posts: 105
Joined: Mon Oct 28, 2019 2:27 am

Re: Replacing the house batteries

Post by Robert K »

Decided to go with the durscells. going to fit pressure treated in the battery tray and strap batteries down . Will have to remake the cables for the 6 volt hookup
Bob
96 Serengeti 37'
3126 Cat
6 speed Allison
2011 jeep wrangler towd
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: Replacing the house batteries

Post by TDJohn »

Robert K wrote: Sun Aug 02, 2020 7:05 am Decided to go with the durscells. going to fit pressure treated in the battery tray and strap batteries down . Will have to remake the cables for the 6 volt hookup
The parallel cables you should be able to reuse if they are in good shape. You will just need to make two of the short series cables.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
Robert K
Posts: 105
Joined: Mon Oct 28, 2019 2:27 am

Re: Replacing the house batteries

Post by Robert K »

Well I got the duracells in after modifying the battery box. Plugged in the shore power and the inverter/converter made a grinding like noise and now no 12 volt from converter. No smoke or burning smell but it probably is not good.
I know there should be a big fuse somewhere.
I don't know if the 4 batteries at 12.7 and the 2 chassis batteries on a trikl start were to much
Bob
96 Serengeti 37'
3126 Cat
6 speed Allison
2011 jeep wrangler towd
wolfe10
Posts: 222
Joined: Sun Oct 27, 2019 4:12 pm

Re: Replacing the house batteries

Post by wolfe10 »

Bob,

Verify that they are hooked up properly. 12.7 VDC would NOT be a cause of issues for a converter or inverter/charger.
Brett and Dianne Wolfe
Ex: 2003 Alpine 38'. Ex 1997 Safari Sahara. Ex 1993 Foretravel U240
Moderator, FMCA Forums 2009-2020
Chairman, FMCA Technical Advisory Committee 2011- 2020
Moderator, http://www.dieselrvclub.org/ (FMCA chapter) 2002-
Robert K
Posts: 105
Joined: Mon Oct 28, 2019 2:27 am

Re: Replacing the house batteries

Post by Robert K »

After putting all the jumper wires on I tested pos out to ground 12 -13volts in that neiborhood
It is a 25 year old unit maybe coincidents
Bob
96 Serengeti 37'
3126 Cat
6 speed Allison
2011 jeep wrangler towd
Post Reply